The eigenmode of a hollow waveguide with two curved surfaces was analyzed with Helmholtz equation and the transmitting efficiency of the hollow waveguide was analyzed with a ray optics approach.

通过亥姆霍兹方程研究了双弯曲截面柔性波导的本征模式；运用光学方法计算了波导的传输效率。

The five-grid difference format of Helmholtz equation in slanting coordinate have been derived.

推导出斜坐标系下，亥姆霍兹方程的五点差分格式；

Only positive Helmholtz equation is considered in beam propagation method, while the negative component is approximately zero.

在光束传输法中只分析前向亥姆霍兹方程，而后向分量近似为零。

The seven-grid difference format and nine-grid difference format of Helmholtz equation in right coordinate in the way of Taylor series method have been derived.

用泰勒级数法推出直角坐标系下亥姆霍兹方程的七点差分格式和九点差分格式；

In this paper, an analytical local orthogonal. coordinate transform and an analytical equation transform are constructed to flatten the interfaces and change the Helmholtz equation as a solvable form.

然而，局部解析坐标变换方法需要满足在两个相邻界面之间存在一条水平直线的介质可分性条件。

We use the FEM to solve the Helmholtz equation in the interior of the antenna and use the boundary-integral method to determine the fields exterior to the antenna.

用有限元法解决天线内部的赫尔姆霍兹方程；用边界积分法确定天线外部的场；

The method can make it more approximation to Helmholtz equation and it's answers include WKB approximation.

该法可以更加近似赫姆霍兹方程，且它的解中包含WKB的近似值。